1. Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
2. Department of Veterinary Pathology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan
3. Department of Veterinary Surgery, Faculty of Agriculture, Gifu University, Yanagido, Gifu, Japan
4. Yamada Animal Hospital, Ichinomiya, Aichi, Japan
5. Veterinary Hospital, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan